/* 背景 */
*{ margin: 0; padding: 0; }
ol,ul,li{ list-style: none; }

/* 游戏区 */
.wrapDiv{
    width: 500px; height: 500px;
    background: #ddd;
    margin: 20px auto;
    overflow: hidden;
    position: relative;
}

/* 飞机 */
.planeDiv{
    width: 40px; height: 40px;
    /* 鼠标移至目标变更为手型 */
    cursor: pointer;
    position: absolute;
    background-image: url('../img/airBg.png');
    background-repeat: no-repeat;
    /* 这是让背景图和容器, 大小一样 */
    background-size: contain;
}

/* 子弹 */
.bulletDiv{
    width: 5px; height: 30px;
    background: #f00;
    border-radius: 100px;
    position: absolute;
}

/* 目标 */
.targetDiv{
    width: 60px; height: 50px;
    position: absolute; top: -60px;
    background-repeat: no-repeat;
    background-size: contain;
}

/* 爆炸 */
@keyframes mymove{
    from { opacity: 1; }
    to { opacity: 0; }
}
.no_boom{ background-image: url('../img/target_icon.png'); }
.yes_boom{
    background-image: url('../img/boom.png');
    animation: mymove 0.2s;
    animation-fill-mode: forwards;
}